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Upgrading binocular coatings

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#1 brocknroller

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Posted 24 June 2006 - 10:52 AM

Is it possible to upgrade optical coatings?

If I had a binocular with coated or fully-coated optics, is there some place I could send it to be made into a fully multi-coated binocular?

Thanks!

#2 EdZ

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Posted 24 June 2006 - 11:04 AM

The thickness of optical AR coatings is measured in 1/4 wavelength. Proper thickness is critical to performance of the coatings. Improper thickness results in reflective coatings, not anti-reflective performance. The thickness cannot be measured on the glass. It is measured during the application of the coatings in the chamber by the change in frequency of light off of a quartz blank.

In order to apply new coatings and insure proper thickness, the original coatings must be remove. You can't do that without changing the figure of the glass. See the recent thread about removing ruby coatings.

The short answer is NO.

#3 brocknroller

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Posted 24 June 2006 - 01:22 PM

Thanks, Ed.

Too bad, the dearth of FMC high-quality porros could have been offset by upgrading the coatings on some of the old classics.

#4 Bob W6PU

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Posted 24 June 2006 - 02:38 PM

With enough money available....All Things Are Possible! :lol:

Good luck!
Bob

#5 DJB

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Posted 25 June 2006 - 03:19 AM

Hi Ed,

I may be misconstruing what you are saying, but if you look starting on page 129 in "Choosing, Using & Repairing Binoculars" (J. W. Seyfried © 1995), he states that this is possible ONCE an appropriate lab is found, cost not withstanding.

Did you mean a proc. for the ruby lens coatings only? I'm a little in the dark here.

I must add that we actually did this three or so times with our coating vendor who supported our lab. We (the lab) were adamant that the optic NOT be refigured in any way whatsoever (which was beyond the means of the coating house anyway).

It was "black hole" MIL stuff, so I can only say the following. It involved a very large optical surface that was softer than glass. Because of coating problems, some pieces had to be recoated. The removal was basically an ELECTRO-CHEMICAL process, and it did NOT affect the figure of the surface. I am not certain how this might come into play with the FMC that we see today. We coated out at three layers max!

However, all of that aside, the question remains for the consumer: Is it worth it? I highly doubdt it. The few percentage gain in transmission would cost too much per square inch of aperture.

Best regards,
Dave.

#6 EdZ

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Posted 25 June 2006 - 05:37 AM

You will note that Seyfried does not fully explain how or if previous coatings are molecularly bonded to the glass, how the thickness of coatings would be measured or if the added coatings (on top of existing) could be controlled as to precise total thickness.

BTW, on another note, there is nothing to stop you from coating a previously uncoated optic.

BTW2, for those that are wondering, mirror stripping and recoating is completely different than AR coating.

edz

#7 Joad

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Posted 25 June 2006 - 11:14 AM

EdZ's point about coating a previously uncoated binocular raises a possibility. I have read that German military binoculars manufactured during the Second World War could, at least in some instances, be uncoated in order to reduce the amount of dirt and sand that might otherwise adhere to the optics. I suppose that if one were to acquire one of these binoculars (they aren't that expensive) and have them fully multicoated, that would be a possibility.

But I agree with everyone who has indicated that, even if possible, this recoating (or first coating) is really not practical in a cost effective sense. With so many reasonably priced FMC binoculars on the market today, it's a heck of a lot cheaper and easier to find the one that suits.

#8 Pinewood

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Posted 25 June 2006 - 11:42 AM

About fifty odd years, ago, there was a small trade in coating uncoated optics. Often the original manufacturer would do it, at least Leitz did so. As the lenses seem to be coated in jigs, Leitz had the equipment to do uncoated examples of later models, that were in current production.

A correspondent of mine has been able to have binoculars coated, perhaps only single coatings, somewhere in the Czech Republic, but he was dealing with some examples of those uncoated German military optics. To be sure, he was a collector more than a user and wanted a FLAK glass updated.

Clear skies,
Arthur

#9 Bob W6PU

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Posted 25 June 2006 - 06:39 PM

Arthur, if someone has a binocular that is very special to them, and wants to have custom work done to it, I'd be willing to bet that Zeiss, Swarovski, Nikon, you name it, would do the job if you offered them enough money! :lol:

Bob in NM

#10 DJB

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Posted 26 June 2006 - 03:17 AM

Hi Ed,

Yes, I know and agree, the book does not delineate exactly what methods are used. Also, because of the copious grammatical errors in the book, it is hard to read between the lines, which, BTW, drives me to crazy.

Yes, I assumed the coating processes are completely different for mirrors (especially ours) and for glass. That's why I put in the disclaimer about FMC. I've never been in a situation where I was privy to the coating process of binoculars. I'll leave that to the experts, as it were.

Thanks for the update.

Best regards,
Dave.

#11 EdZ

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Posted 26 June 2006 - 04:53 AM

Follow the links to Edmund Optic technical Info. links found in Post pinned at top titled Links to Web.. Edmund techs explain things pretty well.

edz

#12 Robert A.

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Posted 26 June 2006 - 05:52 AM

I does strike me as a market that has some potential. I would dream of updating the coating on some of my collection. I vote for the proposition! Isn't this the new economy? Custom services that people want. Couldn't be made within reach of us? What would that number be? $100 or $200, or rarely $300?
Who joins my vote?

#13 Joad

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Posted 26 June 2006 - 09:49 AM

Eeeek. I sure don't want to vote against. But from my various tutorials on Cloudy Nights (as a student, not an instructor!), I believe I've learned what a full multi-coating would entail. Let's assume previously uncoated optics (so we don't have to consider the impossible task of removing the old coatings). Now, to be FMC, all glass surfaces must be coated: that includes prisms, ocular elements, and objective lenses. The re-coater would have to disassemble the entire binocular, possibly breaking cement bondings to do so, submitting each element to the molecular coating process, then reassembling the binocular in perfect collimation. Could it done? I assume it could: after all, you have to disassemble a binocular to repair it sometimes. But could it be done cheaply? As cheaply as $300? Aye, there's the rub (lifted from Hamlet's soliloquy).

#14 gatorengineer

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Posted 27 June 2006 - 08:54 AM

Ok, let me up this up to some flames, from the purists here.....

It can be done, and I have done it, with both german flaks and old B&L 7x50s. There are a number of firms that do this work, Majestic Optical coatings did some, with in my opinion very good result. (Another firm did some more, with less positive results) just type in Optical coatings into search engine, and start dialing the phone.

To remove old coatings auto windshield polish is very gently used. Yes I know it can change the figure of the glass, but with typical mags used in binos, I dont think it can be seen.

Cost is about $200 for a run, depending upon the coatings selected. HAVE FUN.

Mark

#15 Joad

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Posted 27 June 2006 - 09:45 AM

Well how about that. No need for flames. If you've done it, it can be done. I stand corrected.

#16 Pinewood

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Posted 27 June 2006 - 10:00 AM

If your binocular was disassembled for cleaning and repair, then the incremental cost would not be that great. I do not see why lenses would have to be uncemented as only glass to air surfaces are coated. Finally, you would still see a big improvement if the prisms were left uncoated, but if you wanted to do this, you may not be interested in doing it cheaply.

Clear skies,
Arthur

#17 gatorengineer

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Posted 27 June 2006 - 10:45 AM

Well the lenses were decemented, and after coating recemented. We initially tried to run them cemented, and the temperature it takes to put a multicoat on the lenses was not tolerated by the cement (it turned opaque). So the lesson learned was decement, and then recement after coating. Coating in the chambers is vaporized and deposits on the upward facing surfaces, and the interior surfaces of the lenses were not coated, but re-glued together using Summers Optical cement (they are very helpful in choosing a cement and providing advise.) last word of advise is to take a black permanent marker and mark the edge of the lens for alignment purposes, and to also keep the "left side" optics separate from the "right side". The left / right thing may not really mater, but we did it just in case.

The we is my friend Steve, who has some navy optical shop experience, and was doing his own binos for a number of years.

Mark

#18 Joad

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Posted 27 June 2006 - 10:51 AM

"There is nothing you can do that can't be done."

John Lennon

#19 BillC

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Posted 27 June 2006 - 02:06 PM

"I am the egg man; they are the eggmen; I am the walrus."

John Lennon

Ah, 'ya just don't get such deep, thought provoking lyrics, anymore.

Cheers,

Bill


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